M3.1 Earthquake 222 km W of Petrolia, CA — July 21, 2026
2026-07-21 22:40:48 UTC (2026-07-21) · approx. 2:40 PM UTC-8 local
On July 21, 2026 at 22:40 UTC, a magnitude 3.1 shallow crustal earthquake struck 222 km W of Petrolia, CA, at a depth of 10.0 km and coordinates 40.4233°, -126.8987°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 651 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 82 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-126.8987°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.1 earthquake near Petrolia, CA?
The magnitude 3.1 earthquake that struck 222 km W of Petrolia, CA on July 21, 2026 at 22:40 UTC had a depth of 10.0 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.1 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: nc75403337). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, July 21, 2026). M3.1 Earthquake 222 km W of Petrolia, CA — July 21, 2026. Retrieved August 1, 2026 from https://www.earthquaketracker.org/earthquakes/event/nc75403337/